Harvard Law School's Laurence Tribe accepts an award from the ACLU in 2011.

Democrats and the mainstream media have spent the months since Donald Trump's election fixated on the the flood of unconfirmed reports, half-truths, and outright propaganda that accompanied his rise.

But some of the country’s leading liberal lights — respected figures including elected officials, prominent legal scholars, members of the media, and celebrities — are themselves sharing wild allegations about the Trump administration from unreliable sources.

Perhaps no one embodies this trend so well as Laurence Tribe. Tribe is one of the country’s foremost constitutional lawyers, the Carl M. Loeb university professor at Harvard Law School. He has argued dozens of cases in front of the Supreme Court. He’s a major figure in American public life, and in recent months Tribe has devoted much of his activity on Twitter to outraged extrapolation about the Trump administration. Often, these take the form of “big if true” tweets that cite unconfirmed reports about Trump’s possible misdeeds and are essentially conjecture.

On April 22, Tribe shared a story from a website called the Palmer Report — a site that has been criticized for spreading hyperbole and false claims — entitled “Report: Trump gave $10 million in Russian money to Jason Chaffetz when he leaked FBI letter,” a reference to the notorious pre-election letter sent by former FBI director James Comey to members of Congress that many have blamed for Hillary Clinton’s November loss.

The “report” the article points to is a since-deleted tweet by a Twitter user named LM Garner, who describes herself in her Twitter biography as “Just a VERY angry citizen on Twitter. Opinions are my own. Sometimes prone to crazy assertions. Not a fan of this nepotistic kleptocracy.” Garner, who has 257 followers, has tweeted more than 25,000 times from her protected account.

“I don't know whether this is true,” Tribe’s tweet reads, “But key details have been corroborated and none, to my knowledge, have been refuted. If true, it's huge.”

Reached by email, Tribe said that he was aware of the Palmer Report’s “generally liberal slant” and “that some people regard a number of its stories as unreliable.” Still, he added, “When I share any story on Twitter, typically with accompanying content of my own that says something like 'If X is true, then Y,' I do so because a particular story seems to be potentially interesting, not with the implication that I’ve independently checked its accuracy or that I vouch for everything it asserts.”

Asked whether he had considered his role in spreading unconfirmed information, given his stature in American society, Tribe responded that “I really don’t have anything to tell you about my thoughts regarding my personal role in sharing information over social media in this usually agnostic manner.”

Tribe is far from alone among prominent liberals in sharing unconfirmed, speculative, and sometimes wild information. But he is emblematic of an information echo chamber that has grown up since the election around sites like the Palmer Report and figures like the anti–Russian influence crusader Louise Mensch, in which anti-Trump public figures share unreliable information, the very act of which the sources of these reports use to bolster their own legitimacy. It therefore operates similarly — though it is smaller and far less powerful — to the vast new right-wing online media that launders dubious claims through increasingly mainstream outlets before, sometimes, reaching the highest levels of government.

The Palmer Report is the work of Bill Palmer, who describes himself on his website as a “political journalist who covered the 2016 election cycle from start to finish.” Before the Palmer Report, Palmer ran a site called Daily News Bin, which Snopes’s Brooke Binkowski said was “basically a pro-Hillary Clinton 'news site.' It was out there to counter misinformation.” Last November Palmer introduced his new site as an “investigative reporting...side project,” and he has since written hundreds of articles that range from “evidence-free” assertions that Vladimir Putin personally ordered last month’s chemical attack in Syria to a story entitled “Brain specialist doctor believes Donald Trump’s frontal lobe is failing” that was based on a single tweet by a doctor. Along the way Palmer has collected more than 63,000 Twitter followers and more than a few famous signal boosters.

Indeed, the site includes a “Thank Yous” section, a long list of liberal notables who have shared the site’s stories. It includes MSNBC host Joy-Ann Reid, Harvard Law School Professor Laurence Tribe, novelist Joyce Carol Oates, director Rob Reiner, Trump foil Rosie O’Donnell, and Mark Hamill, aka Luke Skywalker. The Democratic California Congressman Ted Lieu is specially thanked for sharing a Palmer Report story on his official website.

Lieu's office did not respond to a request for comment.

The site had its most significant exposure yet this week. As confusion swirled in Washington Wednesday following Trump’s firing of Comey, Democratic Massachusetts Senator Ed Markey went on CNN to make an explosive claim: A grand jury had been empaneled in New York to investigate Trump’s ties to Russia. (Another grand jury investigation, in Virginia, has been reported by CNN.)

And what were Markey’s sources for this alarming claim? According to a Guardian reporter and the Daily Caller, none other than the Palmer Report and Mensch themselves. Hours after making the claim, Markey was forced to apologize for spreading unsubstantiated information, and, through a spokesman, to reveal that he had no direct knowledge of any New York investigation.

Markey's office did not respond to a request for comment.

And despite Markey’s apology, as of Thursday afternoon, the Palmer Report headline read: “U.S. Senator confirms grand jury is now underway in Donald Trump case in New York State."

Joe Bernstein is a senior technology reporter for BuzzFeed News and is based in New York. Bernstein reports on and writes about the gaming industry and web culture.